What's the difference between type 1 and type 2 diabetes?

Type 1 is autoimmune destruction of insulin-producing beta cells, usually presenting younger, requiring insulin from diagnosis. Type 2 involves insulin resistance with progressive secretory decline, is strongly linked to weight and genetics, and is managed with lifestyle, oral drugs, and sometimes insulin.

Type 1 requires insulin because the body produces almost none. No diet or tablet can substitute for it, and stopping insulin is life-threatening.

Antibody testing and C-peptide levels can distinguish the two when the picture is unclear, which matters because treatment differs fundamentally.